Multioffice telephone system



Filed Oct. 25, 1943 2 Sheets-Sheet 1 I INVENTOR.

FOP/WIND. EGO/M454 MULTIOFFICE TELEPHONE SYSTEM Filed Oct. 23, 1943 2 Sheets-Sheet 2 INVENTOR.

Patented Apr. 26, 1949 MULTIOFFICE TELEPHONE SYSTEM Fernand P. Gohorel, Antony, France, assignor to International Standard Electric Corporation, New York, N. Y., a corporation of Delaware Application October 23, 1943, Serial No. 507,470 In France February 24, 1939 Section 1, Public Law 690, August 8, 1946 Patent expires February 24, 1959 This invention relates to new and useful imwhich the operator at the outgoing exchange controls the establishment of connections without the intervention of the incoming or a tandem operator.

The objects of the present invention are to provide certain modifications of the system shown in my Patent No. 2,431,321, issued November 25, 1947, in order to obtain more certain operation of the register, and to permit the reception of the dialling impulses in the form of trains of impulses instead of spaces or interruptions in the dialling current.

In accordance with the invention, in the case in which the impulses are transmitted in the form of trains of impulses, the release of the register and. of the detector at the end of the reception of the impulses, is effected without counting the number of trains of impulses received. For this purpose an impulse is sent from the outgoing exchange at the end of dialling when, for example, the operator releases her dial key of the cord pair. This impulse causes at the incoming exchange, the release of the register and of the detector.

The various characteristic features of the invention will more clearly appear from the following description with reference to two embodiments diagrammatically illustrated in Figs. 1 and 2, which show as much as is necessary for understanding the invention and which are given by way of non-limiting examples.

First, the operation of a modified register in Fig. 1 will be explained, this register being provided to receive the impulses transmitted in the form of spaces in a dialling current. In this connection attention is directed to the above-mentioned co-pending application.

When earth is applied to starting wire 52, relay 28 is energized on its lower winding. At the end of the testing of the detector associated with the register, earth is applied to wire 23 which operates relay on its lower winding. The automatic stepping circuit of finder C03 is completed. The wipers of this switch hunt for the incoming equipment on which the call has been received. When this equipment has been found, the circuit of relay 29 is completed and this relay pulls up and stops the wipers of C03 by opening the circuit of magnet Cma. The circuit of the upper winding of relay 30 being now completed, this relay falls back. The circuit of relay 32 is completed.

When relay 32 pulls up, the register and the 2 Claims. (Cl. 179-27) 2 detector equipment are connected to the incoming equipment.

After the free equipment of the automatic switch has been connected to the incoming equipment, relay 40 pulls up.

When the dialling current transmitted by the outgoing exchange is received at the incoming exchange, relay 35 pulls up and completes at T362 the circuit of relay 2, which pulls up after amoment;

As disclosed in the co-pending application, upon each disconnection of the dialling current relay 34 is energized, and through T342 and T22 completes the circuit of relay 38 which pulls up. At the end of the disconnection of the voice frequency current corresponding to one impulse, relay 34 falls back. Relay 38 is held and the upper winding of relay 31 is energized to complete the circuit of magnet Cmi.

The magnet Cmi advances wipers C01 by one step causing the release of relay 38 which shortcircuits the lower winding of relay 31. This relay is sufliciently slow to remain up while a train of impulses is transmitted.

The wipers C01 of 01m thus advance one step upon each impulse received.

At the end of the reception of the train of impulses, relay 31 and relay 36 are de-energized, and the charging of the condenser connected to the bank of C01 will take place. The various trains of impulses are registered.

The manner in which the re-transmission of the impulses takes place will now be explained.

When relay 35 pulls up, it completes the following circuit for relay 5: battery, winding of 5, R44l, R392, T40I, T352, T32l and earth. After a moment relay 5 pulls up and at T5| completes the energizing circuit of relay 42. Relay 42 pulls up after a brief delay and completes at T423 the following circuit of relay 4|: battery, winding of 4|, T423, R52 and earth. After a moment relay 4| pulls up, and relay 43 is energized to complete through T43| the control circuit of magnet Cmz of switch 002. Through T432, it completes the impulse repeating circuit.

The repetition of the impulses and the advance of the switches C01 and C02 take place now.

When relay 42 falls back it opens at T423 the circuit of relay 4| and at T422 it removes the short-circuit from relay 5. Relay 4| having returned to normal, completes the impulse circuit and relay 40 being energized, opens at 40| the circuit of relays 43, 44 and 45, which fall back.

As soon as relay 44 falls back, the circuit of relay 5 is again completed, whereupon a fresh train of impulses is retransmitted, as above described.

At the end of the dialling, the restoration of the register to normal takes place.

Fig. 2 shows a register similar tQthat of Fig. 1, but which has been adapted by very simple modification to receive dialling impulses in the form of trains of impulses.

The impulse relay 34 is no longer connected-mo. .wire 26 of the detector, but. to wire 25' which is disconnected from relay 3B; When relay 32 is energized, the following holding. circuit for relay, 36 is completed: battery, R354, T326, winding of 3 6 and earth.

The impulses are received upon each pullingup of the impulse relay of the detector (relay 53 of Fig. 5 of the patent above referredlto). Relay 34 pulls up whereupon the register operates as previously described.

When the termination of the dialling impulse signalled to theoutgoingexchange, for example, when the operator releases her dial key, the detector causes the pulling upzofrelay.3 l followed bythepulling up of relays 38, 31,- and 3.5;

The end-of-dialling impulse is long enoughto openthe circuit at R354; soas; to cause the deenergizationof, the slow-acting relay 36 which is not released during theopeningof R354- upon the reception ofv the dialling impulses,

The other operations in the register are the same as:in the: previous case.

What isclaimed, is:

1. In a telephone system, a. plurality of ex.- changes, lines terminating at said exchanges, trunk lines interconnecting said exchanges, op; erators positions. at. said. exchanges, an. impulse deviceat the calling exchange operatorsposition operable in accordance Withuthenumer-ical d'esig; nation of a called line, a, source ofvoicefrequency current at the calling exchange from which trains of current impulses are sent over a trunk line to the called exchange under the control of theimpulse device, a register controller at the called exchange-variably operable; by said impulse device, automatic selector switches at the called exchange adapted to select a called line and operable under the control of said register controller,,means at the called exchange for connecting said register controller with the trunk line. through which the calling exchange is connected with the called exchange, and means at the calling exchange for sending an impulse towards the called exchange upon the termination or theoperation of said impulse device for releasing said register controller.

2. The telephone system according to claim 1, and a key at the calling exchange operators position for connecting, when operated, the impulse device With a trunk line, said key constituting the last-mentioned means, being adapted uponitsreleaseto send theregister releasing impulse towards the called exchange.

FERNAND P. GOI-IOREL.

REFERENCES CITED The following references are of record in the fileof this patent:

UNITED STATES PATENTS 854,039 France Apr. 3, 1940 

